How to reach Thurgadin
Thurgadin is the city of the ice dwarves located in the northern most portion of The Great Divide. Depending on what expansion pack it is will determine the route you'll take here. If Planes of Power is out on your server then you can take the PoK book to Great Divide and Thurgadin is a hop skip and a jump away.
Players on P99 or during Velious looking to reach Thurgadin will have less options. You'll need to find a Druid or Wizard to port you to Great Divide then you'll have to run north to Thurgadin or if you can't find any ports at all you'll have to take a boat from North Ro to Iceclad and hoof it across East Wastes to get here.
For those unfamiliar with Thurgadin you may be surprised to find that you need to run through an invisible wall to reach it. In the screen shot below I am standing just outside the entrance to Thurgadin. A blue box on the screen shot marks the location of the invisible wall you must travel through.